John Deere Z645

The John Deere Z645 zero turn mower is powered by a 27 hp twin cylinder engine. This 0.724 liter engine is lubricated using a full pressure lubrication system that has a capacity to hold up to 1.7 liters of oil. The air cooled engine is fed with gasoline from a fuel tank that can hold up to 13.2 liters (3.5 US gallons) of gas. Power from the engine gets to the wheels thanks to a dual hydrostatic transmission which makes operating and controlling the JD Z645 very easy once you get used to the twin lap bars in front of you.

The transmission gives the John Deere Z645 zero turn mower a top speed of 14.5 kph (9 mph) which makes it perfect for cutting grass on large open playing fields where you can really utilize this high top speed. As the JD Z 645 is a zero turn mower, the front wheels have little function other than keeping the machine balanced. All the turning is controlled by the rear tires. As a result, the front tires are small and offer little friction. They measure 13×6.5-6 (13 inch diameter, 6.5 inch width, 6 inch rim diameter), while the rear wheels have a much ‘grippier’ thread and are a lot bigger. They measure 23×10.5-12 (23 inch diameter, 10.5 inch width, 12 inch rim diameter).

Sitting and operating the John Deere Z645 lawn mower during long operating hours is not particularly uncomfortable. This is thanks in part to the fact that the driver’s seat has a high back and spring suspension. It is also adjustable so that you can choose a setting that is most comfortable for your height. The mower deck itself on the JD Z 645 has a cutting width of 48 inches and can be adjusted from as high as 4 inches above the ground to as low as 1 inch above the ground. Similar models include the John Deere Z510A and the John Deere Z520A lawn mowers.

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10 Reviews of the “John Deere Z645”

  1. Tom says:


    Year of Manufacture: 2014
    Pros: What a great mower. We have 3 acres of park with mature oak trees throughout and another 5 acres of horse paddocks. This Z645 makes this job so easy and is a grass gobbling machine. Better than I could ever have imagined and makes my life so much easier. The 62″ deck makes fast work of what used to take me an entire weekend; now done in a day. And, I don’t feel tired like before, which as age 67 is amazing. I read some people saying they are not easy to start – no such problem here. Just pull up the chock at same time as turning the key and it starts within 2 seconds. This machine has never bogged down and never let me down.
    Cons: Changing mower blades is not so easy.

  2. J dun says:

    This is agreat mower. Very fast a comfortable . Done lots of research before buying. I looked at about all zero turn manufactors before I made a purchase . I was a little unsure about the Briggs motor on a 6000 dollar machine. But I took a chance and went with johndeere because I love their products . So far I love my z645 by far the best residential mower around. Time will tell about the Briggs but mower comes with a great warranty so I feel ok with it. If you are looking for a great residential zero turn you can’t go wrong with the z645.

    Year of Manufacture: 2012
    Pros: Great mower cut time half very fast
    Cons: Takes. A few sec to start even when warm

  3. Tom says:

    This 2011 Z645 mower burned my grass whenever it took more than a couple of seconds to turn around. I spoke to my John Deere dealer and discovered that the 2012 Z645 has a thicker and wider muffler guard. The muffler and guard also are 1/2 inch higher than the 2011 version. My dealer told me that they would install the new muffler and guard assemblies under warranty, which they did. No more burn marks at all.

    The choke does have an adjustment. There is a small circular disk near the cable attachment point on the engine. This disk has a triangular mark on it and this must point straight down when the throttle is at start/choke position. This can be done by moving the knob to the start/choke position, then loosen the cable clamp and slide the cable and cable housing until the triangle mark is straight down. Tighten the cable clamp and the engine will start in one second of cranking. Your dealer can also do this for you in warranty.

    I was initially concerned that the fuel tank only held 3.5 gallons, because my old zero-turn held 5 gallons. However, I quickly learned that I am burning less gas with this new, bigger, heavier, and more powerful mower. It doesn’t need to hold five gallons.

    I have a couple of low spots that get muddy after heavy rainfall. My old mower would get stuck. My Z645 John Deere has never even dug down into mud because the rear tires are so large.

    Year of Manufacture: 2011
    Pros: Well made, strong frame, powerful, great cut, comfortable, and great fuel economy. Deck handles all the grass you can give it. This is a great zero-turn lawn mower.
    Cons: None, once the 2012 muffler and muffler guard were installed (under warranty) to stop the burning of my grass. Read my general comments.
    Attachments: Foot rests, trailer hitch
    Modifications: None

  4. jazz says:

    I have a 5 ft belly deck for my 3520 but it is slower than my 645z with the high cap deck. The 3520 deck is so heavy to put on and take off I got sick of this wrenching on my back each time. I do love the zero turn and think this is the only way to go if you have trees and alot of close quarters. Don’t get me wrong it flies in the open spaces too. But if you’re lawn is large and rough you might want to think about how the zero turns feel after about 3 hours of bouncing around. Try one out first.

    Year of Manufacture: 2011
    Pros: Mowing is fast and easy and not alot of time wasted around anything. Blades are easy to remove and put back on. The seat is very comfortable for me and I mow about 4 acres and I have a bad back. The dealer is only 15 miles away is another reason I bought green. I also own a JD 3520 and no troubles. I do like the engines easy accesse to the head area for easy cleaning and the air filter is a nice addition. The four year warrenty.
    Cons: Poor starting at first till I brought it to dealer and he adjusted the throttle cable and it starts in abought 11/2 to 2 secounds. I too have no love for the choke at full throttle postion. Come on are you saving about $15 per unit with this. I’d pay for a seperate choke. What Management team went with this, poor thinking. The hydro has no cooler and needs it badly. The plastic tank for the hydro is so soft it feels like it’s going to melt. I’d like to add a hydo cooler which I bought but I’m afraid it’ll void the 4 year warrenty.
    Modifications: I would like to add Hydro cooler.

  5. Dan says:

    The Z645 is just plain hard to start. I bought mine in June 2011 and now Nov 2011 my battery is dead. I took it to a JD dealer and they told me that my battery was dead and they recharged it. i came home installed the battery and crank about 6 times and the battery die again. 6 months with a new battery and now it’s dead. I went to Lowe’s and bought me the 50.00 battery for up to 38hp mower. I installed the new battery and crank it two times before it started. i also bought some fuel cleaner from the dealer due to the 10percent ethanol. Dealer told me that I need to keep adding it to the gas. What will happen when gas increases the ethanol to 20 or 40 percent? I hope JD comes out with a modification. I hate to spend 7K and not be able to use my mower.

    Year of Manufacture: 2011
    Pros: Good and fast.
    Cons: Burn grass if stopped for more than 13 seconds.
    hard to start
    muffler too close to the ground.
    hand brake to far down.
    Attachments: none

  6. jazz says:

    had it for a month and do like the construction and ease of use along with the comfort built into it.

    Year of Manufacture: 2011
    Pros: Great job of mowing all types of grasses, Strong frame and good traction from the rear tires seem to be of good quality. Seems easy to work on for standard maintance. The eangine is easy to keep clean being it is air cooled and can build up a blockage in the fin area and burn up the heads. I like the fact the dealer is only 9 miles down the road and on my way to work. One of the biggest reasons I own the green and I also have a 2007 3520 tractor with no troubles.
    Cons: The full postion choke I hate. I would perfer a seperate choke and throttle lever. The 27 hp briggs is a hard starter when cold a lot of starter time before it starts. I would say it cranks for at least 5 seconds before starting. The drive pump seems to get very hot and I wish they had a oil cooler on it.
    Attachments: none
    Modifications: I bought a hydraulic oil cooler for it, now just need to find the right spot and level for it.

  7. Roger S. says:

    The first time I mowed I used the wash port after mowing which worked great but beware setting in one place and running will burn your grass. Yes, I said that right BURN your grass! I found that if I let the mower site in one spot no more than 15 seconds it will scorch the grass bad enough that it dies. I first though it was me but tried it in and area out of the way and it didn’t make any difference whether it was in idle or full throttle. JD said they were aware of the problem and were working on a fix. My question was why wasn’t I told this before purchase. My suggestion is to keep it moving or burn the grass. I hate to think about what might happen this fall with dry leaves when mowing.

    Year of Manufacture: 0
    Pros: Plenty of power,great speed, quality cutting even at high speed, well made.
    Cons: BURNS your grass!

  8. Rick says:

    Upon delivery of the mower, the engine would not start. The dealer had the choke linkage adjusted and the engine has run flawlessly since. I did alot of research on zero turn mowers before I bought the John Deere .For the price, quality and dealer support I am completly satisfied so far.

    Year of Manufacture: 2011
    Pros: The power, speed and cut quality of this mower.
    Cons: Had to have the choke adjusted upon delivery.

  9. Dale says:

    very happy, pls I have a full 4 year warranty on the entire mower including the engine

    Year of Manufacture: 2011
    Pros: smooth ride
    smooth hydraulics, steers and handles well
    clean smooth cut, cutting st augustine grass with it
    Cons: I’m not real happy with the effort required to start the 27 hp briggs motor
    seems like even when the engine is warmed up, it doesn’t start very easy
    Attachments: stock
    Modifications: none

    • Vaillantf says:

      My brother just got one and we couldn’t even get the engine to start. It seems that the choke is not properl y adjusted somehow but there’s not much adjustments and nothing is specified for this in the manual.

      Year of Manufacture: 0
      Pros: Fast, strong.
      Cons: Starting the engine is a mess.

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